As computers have become increasingly interconnected via networks such as the Internet, many computing devices have been increasingly vulnerable to access by unauthorized users. Unauthorized users, or “hackers,” are continually using more intelligent and sophisticated methods of breaking into computer users' accounts than previously encountered by computer security personnel. To guard against hackers, counterintelligence methods must, by necessity, also must become more intelligent and sophisticated.
Since hackers often make multiple attempts to login to a targeted computer by randomly trying each of a list of commonly used passwords, one important counterintelligence method is the recognition of false passwords. One current method of detecting false passwords is to look for “alert” passwords, or those likely to be included in such a list of commonly used passwords. Although alert passwords can reduce false positives with respect to detecting break-in attempts, the method may also produce an unacceptable number of false negatives.
Other false password detection methods include analysis of the timing of keystrokes or other keystroke dynamics of password attempts. For example, some of these types of biometric authentication techniques examine the duration of and latency between keystrokes during password entry. However, these methods do not compare entered passwords to actual stored, valid passwords.